Comments

Add Win64 SEH unwind codes for the ABI test trampoline.
This is all manual right now. Once we've added SEH tests, we can add support
for emitting these in x86_64-xlate.pl, probably based on MASM and Yasm's unwind
directives, and unify with CFI. (Sadly, NASM does not support these
directives.) Then we can push that upstream to replace the error-prone and
non-standard custom handlers.
Change-Id: I5a734fd494b7eaafab24a00e6df624bd03b37d43
Reviewed-on: https://boringssl-review.googlesource.com/c/33785
Reviewed-by: Adam Langley <agl@google.com>
Reviewed-by: Adam Langley <alangley@gmail.com>
Commit-Queue: David Benjamin <davidben@google.com>